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Home , Lead smelting, Tailings

Ensvironmental Health Perspectives Vol. 28, pp. 23-37, 1979

Cadmium in Forest Around Smelters in Missouri by Nord L. Gale* and Bobby G. Wixsont

The development of Missouri's new lead belt within the past decade has provided an excellent opportu- nity to study the dissemination and effects of heavy in a deciduous forest . Primary lead smelters within the new lead belt have been identified as potential sources of cadmium as as lead, , and copper. and operations tend to produce significant quantities of small highly enriched in cadmium and other . At one smelter, samples of stack particulate emissions indicate that as much as 0.21 lb of cadmium may be released to the atmosphere per hour. This is accompanied by 0.44 lb zinc, 4.66 lb lead, and 0.01 lb copper/hr. These point-source emissions, as well as a number of other sources of fugitive (wind blown) and waterborne emissions contribute to a significant deposition of cadmium in the surrounding forest and stream beds. Mobilization of vagrant heavy metals may be significantly increased by contact of baghouse dusts or scrubber slurries with acidic effluents emanating from acid plants designed to produce H2504 as a smelter by-product. Two separate drainage forks within the Crooked Creek watershed permit some comparisons of the relative contribu- tions of cadmium by air-borne versus water-borne contaminants. Cadmium and other heavy metals have been found to accumulate in the forest and partially decomposed litter along stream beds. Greater solubility, lower levels of complexation with organic ligands in the litter, and greater overall mobility of cadmium compared with lead, zinc, and copper result in appreciable contributions of dissolved cadmium to the watershed runoff. The present paper attempts to define the principle sources and current levels of heavy contamination and summarizes the efforts undertaken by the industry to curtail the problem. Introduction belt (Fig. 1). The recent and rapid industrial de- velopment within the Clark National Forest, a vast During the First International Cadmium Confer- deciduous oak-hickory forest, has offered a unique ence held in San Francisco, California in February opportunity to study the dissemination of heavy 1977 (1), the principal sources of environmental metals and environmental effects within this type of cadmium were identified as: (a) the primary , milling and of nonferrous metals and (b) secondary processing and operations. Several reports (2-4) emphasized that cadmium is primarily a by-product of zinc production, with minor recovery during . Dugdale and Hummel (5) presented data on the dissemination of cadmium and other heavy metals from the primary lead smelter at Belledune Harbor in New Brunswick, and discussed the of cad- mium within the conventional Imperial lead smelt- ing process. For the past ten years, a team of investigators (6) has studied the dissemination of heavy metals from the mines, mills and smelters of Missouri's new lead

* Life Sciences, University of Missouri-Rolla, Rolla, Missouri 65401. 5e = MINES = LEAD SMELTERS t Environmental Research Center, Civil Engineering, Univer- -0 sity of Missouri-Rolla, Rolla, Missouri 65401. FIGURE 1. Missouri's new lead belt: the "Viburnum Trend." February 1979 23 ecosystem. Presentation of data relative to the ment of much of the lead concentrate to smelters emission, deposition, and of cadmium in outside the area. this geographic setting offers a useful comparison with past research efforts already cited, and, hope- fully, may be useful in assessing the current en- Environmental Cadmium vironmental status of this potentially hazardous There is little basis for environmental concern metal. about vagrant cadmium from either the mines or Industrial production within the "Viburnum mills of the new lead belt (6). Cadmium content of Trend" or new lead belt of Missouri began in 1967. lead concentrates produced by the mills ranges By 1976 there were seven mine- complexes and from 0.005 to 0.2%, and current levels of exposure two smelters in production. Annual production of to workers or to aquatic ecosystems receiving pro- lead concentrates by the mines and mills now ex- cess waters are not deemed hazardous. Lead smelt- ceeds 500,000 tons, making this area the largest lead ers, on the other hand, have a more serious problem producing region in the world, accounting for ap- with cadmium and must deal with its control along proximately 82% of the total U. S. lead production with the more obvious emissions of lead and zinc. (according to U. S. Bureau of Mines statistics) (6). Figure 2 presents a flow sheet diagram for a typical Considerable quantities of zinc and copper ore con- primary lead smelter. Initially, a mixture of ore centrates are produced as by-products, and are concentrate, sand, and limestone is ignited and shipped elsewhere for smelting. The combined de- roasted in the sintering or desulfurizing operation. sign capacity of the two new lead belt smelters ap- PbS is converted to PbO in this process, and the proaches 260,000 tons annually, necessitating ship- latter is taken to a blast furnace and subsequently

SMELTER

L FIGURE 2. Flow sheet diagram for a typical lead smelter. Courtesy of AMAX-Homestake Lead Tollers. 24 Environmental Health Perspectives reduced to produce metallic lead. Sulfur present in and baghouse dusts may show cadmium enrichment the is converted to SO2 which is by a factor of approximately 42 to 300-fold. Further swept, along with strong updraft currents of air and size fraction of flue dusts indicated that cadmium suspended fine particulates, toward a cooling concentrations are 10 to 15 times higher in the very chamber and baghouse filter or Venturi scrubbers. fine particulates than in the coarser particulates Some smelters pelletize the sinter feed prior to present. Unfortunately, these very fine particles are to reduce the quantity of fine particulate those most likely to escape the baghouse and be material suspended by updraft air currents. swept to the stack for discharge to the atmosphere. Electrostatic precipitators may also participate The concentrations of cadmium in the baghouse with baghouse filters in removing particulates from dust dictate special consideration of these hazard- sinter gases. The cleaned and cooled sinter gases ous materials. Concentrations of accumulated cad- are either released through a tall stack into the at- mium in baghouse dusts of zinc smelters are suffi- mosphere, or in some smelters, the SO2 is con- cient to permit recovery of the cadmium with some verted to sulfuric acid in a single or double- economic benefit. Baghouse material from lead absorption contact acid plant. smelters is only seldom treated to recover the con- The majority (75%) of the cadmium present in centrated cadmium. Accumulated cadmium is, for ore concentrates is volatized at the temperatures the most part, allowed to escape in the form of fine employed during sintering, along with considerable particulate matter from the stack scattered by fugi- quantities of lead (3). Particulate matter collected in tive emission during the handling, storing, and re- the baghouse or scrubber slurry, enriched in cad- cycling of baghouse materials, or appears as im- mium, is periodically removed and cycled back to purities in smelter . When old worn bag fil- the sinter preparation area. A similar baghouse filter ters are removed and replaced, considerable dust serves the blast furnace operation during which re- adhering to the cloth material accompanies the bags sidual cadmium present in the PbO charge may be to disposal sites. Each bag is approximately 25 to 30 volatized and subsequently condensed to form ft long and may have as much as 10 to 20 lb of baghouse dusts. These trapped particulates are also adhering dust. In some cases, the bags are cycled routinely cycled back to the sinter preparation area. back through the sintering process, while some As others have already pointed out (5), there are no smelters haul them to land disposal sites. Careless sinks for cadmium in this process, and its accumu- selection of disposal sites or prolonged storage prior lation over an extended period will produce recycle to recycling, subjecting such to the dusts of relatively high cadmium concentration. A and erosion of rain and wind, may present a signifi- certain portion of finely divided particulates is not cant source of cadmium contamination to the sur- retained by the baghouse filters and escapes via the rounding environment. stack to the atmosphere, depending on the collec- tion efficiency of the sinter gas filtering system. Bolter's (7) analyses of baghouse dusts collected Amax Lead Smelter from new lead belt smelters illustrate this concen- The larger of the two smelters now operating in trating phenomenon (Table 1). Bolter showed that the new lead belt is located at Boss, Missouri and is the ratio of Pb to Cd in ore concentrate is 4000:1, owned and operated by AMAX-Homestake Lead

Table 1. Heavy metals in baghouse dust from AMAX and ASARCO smelters.a ~Cd Source of particulate MetalMetalconcn,ppmconcn, ppm concentration material Pb Zn Cu Cd factor ASARCO Blast furnace, 3/74 268,000 126,000 3,150 59,500 298 Blast furnace, 2/73 352,000 105,500 4,440 47,000 235 Sinter plant, 3/74 272,000 12,480 13,100 30,700 154 Sinter plant, 2/73 248,000 11,900 7,300 32,000 160 AMAX Blast furnace, 2/73 666,000 56,000 4,200 8,300 42 Sinter plant, 2/73 619,700 4,100 400 9,400 47 Flue dust 2/73 623,000 62,200 5,500 19,500 98 Lead concentrate 783,400 23,000 4,900 200 1

a Data of Bolter (7).

February 1979 25 the waters of East Fork generally support a fairly diverse biological community. Though the stream may be classified as a wet weather and disappear- ing stream, there are good stands of cattails in the marshy area immediately adjacent to the smelter trash pile, and during periods of flow, consistent algal growth extending some distance downstream. Further downstream, beyond the sampling station #5 (Fig. 3) as stream flow is somewhat consistent, standing populations of aquatic insects, tadpoles, and minnows are an indication of reasonable stream diversity. Modification in the design of the agricultural lime storage area in 1975 eliminated an earlier problem. In 1977, the ore concentrate storage area at Com- inco American was modified to contain all runoff and eliminate that source of heavy metals to East FIGURE 3. General layout of AMAX-Homestake Smelter and Fork. Much of the water flowing under the track Crooked Creek watershed. Numbered circles indicate sam- and past the industrial trash heap has been diverted pling sites on Crooked Creek. to flow southward into lagoons designed to Tollers, Inc. The general layout of the smelter and treat the mill effluents. Policies regarding disposal surrounding area is shown diagramatically in Figure of baghouse materials by the smelter are currently 3. Design capacity allows production of approxi- under discussion to alleviate the obvious problems mately 140,000 tons of lead annually. This smelter is stemming from improper disposal of hazardous located on a natural divide, at the extreme headwa- wastes. ter area of the Crooked Creek watershed. Drainage The west fork of Crooked Creek receives from the area occurs through the east and west effluents from the sanitary lagoon and the acid forks of Crooked Creek as shown in the diagram, plant, as well as runofffrom the concentrate storage flowing toward a confluence approximately 11/ mile area, the railroad tracks, and much of the smelter to the northwest. Crooked Creek continues to the yard. Impoundment C was created in 1970, and north, joining the Huzzah Creek approximately 6 existed until 1977 as the only sedimentation lagoon miles downstream, and eventually discharges to the to treat industrial effluents and runoff. Meramec River at a point approximately 30 miles Impoundments A and B and the water treatment from the smelter. Proposed construction of a facility were completed in 1977, with the ultimate across the Meramec River would create a reservoir goal of total recycle for all industrial effluent and which would possibly be affected by heavy metals runoff. However, total recycling has not yet been in runoff from Crooked Creek. achieved. The acid plant has a relatively constant The east fork of Crooked Creek drains an area effluent with pH commonly between 2.2 to 3. Ineffi- which may receive runoff from the adjoining prop- cient neutralization of this effluent has been a per- erty of the Cominco American Mine-Mill complex sistent problem, resulting in a long history of acidic as well as the AMAX smelter. Heavy metals may effluents from impoundment C into the headwaters enter East Fork from a number of identified of Crooked Creek. The problem has been com- sources, including the overflow from the pounded by the extremely high heavy metal content granulation , from the industrial trash of sediments in the impoundment. Sediments reflect heap (where in the past many baghouse bags have significant runoff and erosion of concentrate storage been discarded), runoff from the railroad track (a piles. Recycling of the baghouse materials is usually major haulage route for ore concentrates), runoff achieved by truck (supersucker vacuum truck), as from exposed copper concentrate piles stored on the accumulated dusts are periodically transferred the adjoining Cominco American mine property, as from the baghouse to designated storage piles in the well as stack and other fugitive particulate emis- concentrate storage area. Cleanup of contaminated sions. Past contributions of heavy metals and rock equipment was usually done at a convenient fire flour to East Fork have also been traced to - hydrant located immediately adjacent to the acid age from Cominco American's mill tails piled near plant. Fugitive effluents from this procedure have the tracks as a source of commercial agricultural contributed heavy metals to . Analyses of lime. samples from the haulage route for these baghouse Despite relatively high exposure to heavy metals, materials have shown evidence of fugitive heavy 26 Environmental Health Perspectives Table 2. Heavy metals in soils and sediments near AMAX smelter acid plant. Metal concn, ppm Material analyzed Pb Zn Cu Cd AMAX smelter yard soil sample near acid plant 274,000 65,000 9,860 4,930 AMAX smelter yard soil sample near acid plant 137,000 2,200 6,710 5,530 AMAX smelter yard soil sample near acid plant 25,150 1,490 3,370 9,010 Sediments from impoundment C taken near spillway. 137,400 20,700 29,000 (average of9 separate slices taken from 18 in. core sample)r Dust adhering to baghouse bag in refuse pile 37,700 81,700 1,939 6,460 a Data of McAllister (8).

Table 3. Stack particulate emissions from the AMAX lead smelter under normal operating conditions." Emission rateb Test Particulates Lead Zinc Cadmium Copper date Gr/DSCF lb/hr Gr/DSCF lb/hr Gr/DSCF lb/hr Gr/DSCF lb/hr Gr/DSCF lb/hr 2/6/73 0.0122 20.87 0.0029 4.95 0.00027 0.47 0.00011 0.193 8.2 x 10-6 0.0140 2/7/73 0.0240 38.69 0.0026 4.18 0.00016 0.339 0.00010 0.157 8.3 x 10-6 0.0134 2/11/73 0.0111 25.80 0.0021 4.85 0.00021 0.495 0.00012 0.281 5.2 x 10-6 0.0120 1973 avg.c 0.0158 28.45 0.0025 4.66 0.00021 0.435 0.00011 0.210 7.2 x 10-6 0.0131 1975 avg. 0.014 33.3 1977 avg.c 0.037 87.0 aData of Lowsley (9). bAs grains per dry standard cubic ft and as lb/hr. c Unpublished data courtesy AMAX-Homestake Lead Tollers. metals, including hazardous levels of cadmium (Table 2). Table 2 also shows heavy metals concen- trations observed in a typical sediment core col- lected in the shallow waters near the effluent of im- poundment C. The range of cadmium values in samples taken from different levels of the reported 18-in. core was 7,700 to 45,000 ppm. Combined conditions of high heavy metals in the sediments coupled with low pH of effluent has resulted in extraordinary levels of exposure of West Fork to adverse conditions. As a consequence of industrial effluents, the headwaters of the west fork of Crooked Creek are devoid of biological activity for some distance downstream. Below sampling station #2, or within approximately 1/2 mile, the stream begins to re- cover, and persistent growths of algae have been observed. Dominant algal forms were of the genus Hormidium, renowned for its resistance to heavy metals, especially zinc. Both forks of Crooked Creek also receive unde- termined quantities of heavy metals resulting from horizontal transport of aerially deposited particu- lates collected and concentrated in forest litter, but originally emanating from the stack and other fugi- tive sources within the workyard. Cadmium and other heavy metals may escape the baghouses and be released to the atmosphere. Early FIGURE 4. Radial distribution of settleable particulate lead in the studies involving actual stack sampling procedures vicinity of the AMAX smelter. Deposition rate is expressed gave some indication of the quantities of lead, zinc, as milligrams per square meter per month. After Lowsley (9).

February 1979 27 FIGURE 5. Radial distribution ofparticulate zinc in the vicinity ofthe FIGURE 6. Radial distribution of settleable particulate copper in AMAX smelter. Deposition rate is expressed as milligrams per the vicinity of the AMAX smelter. Deposition rate is ex- square meter per month. After Lowsley (9). pressed in milligrams per square meter per month. After Lowsley (9). cadmium and copper released to the atmosphere by centrations in leaves of selected indicator plant the AMAX smelter. The results of these studies are species have been reported by Hemphill (11). Ex- summarized in Table 3. Size fractionation of these tracted data representing heavy metal concentra- particulates confirmed the earlier studies that indi- tions found in white oak and blueberry leaves are cate that cadmium tends to be most highly concen- shown in Figure 8. Low metal concentrations in the trated in the finer particulate fractions with effective leaves of deciduous plants are not as impressive as cutoff diameters less than 2 ,4m. Actual deposition those found for soils and forest litter. of heavy metals was measured at 35 established Bolter (12) concluded from his studies of soils and dustfall stations in the vicinity of the smelter. The forest litter, that heavy metals tended to be highly results of these measurements are plotted as iso- concentrated in the decomposing litter of the forest pleths in Figures 4-7. These data must be consid- floor. Soil profiles taken to a depth of several feet ered as composite samples of air-borne particulates indicate very little downward migration of heavy emanating from the stack and fugitive (wind-blown) metals. Organic ligands present in the partially de- resuspended particulates. composed leaf litter as small particles of debris or In 1974-1975, extensive modifications in the more soluble humic and fulvic acids may act as baghouse and acid plant were made to improve the vehicles for transport of heavy metals throughout efficiency of particulate retention. More recent the litter layer and horizontally into area streams. dustfall data have shown some improvement in the Concentrations of heavy metals in leaf litter speci- amounts of cadmium and copper detected in air- mens taken along a transect between the two smelt- borne particulates (Table 4). ers of the new lead belt are shown in Figure 9. Ab- Heavy metals emanating from industrial opera- solute values of cadmium concentrations ap- tions have resulted in appreciable accumulation in proached 100 ppm at that time (1974) in specimens the surrounding forest. Studies on heavy metal con- closest to the AMAX smelter, dropping down to

28 Environmental Health Perspectives b

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FIGURE 8. Heavy metals in white oak and blueberry leaves near the AMAX smelter: (a) lead in white oak; (b) lead in blueberry leaves; (c) cadmium in white oak; (d) cadmium in blueberry leaves. Values in ppm (dry weight). After Hemp- hill (II). FIGURE 7. Radial distribution of settleable particulate cadmium is ex- in the vicinity of the AMAX smelter. Deposition rate beds occurs as a result of dissolution by acid stream pressed as milligrams per square meter per month. After Lowsley (9). water or saltation and mass transport during storm runoff. Such factors cause considerable variation in metal content of collected specimens, and undoubt- Table 4. Settleable particulate material: edly influence the rate and level of metal accumula- geometric mean of 19 dustfall stations.a tion observed. Observed episodes of released in- dustrial sediments high in cadmium and other heavy Particulates, mg/m2-mo metal contamination are known to dissipate gradu- Pb Zn Cu Cd ally, and represent a continual source of heavy Priorto 1976 35.01 8.24 4.19 0.266 metal contaminants to downstream sites. The east 1976-1977 36.37 8.39 2.61 0.176 fork experiences a greater burden of lead, zinc, and a Data of Lowsley (9, 10). copper than the west fork. But without the pH problems characteristic of the west fork, and de- background levels within 10 to 15 miles. On the spite the observed elevated concentration of heavy particular transect shown in Figure 9, the contribu- metals, biological activity within the east fork re- tion of heavy metals from industrial operations of mains reasonably normal. parame- the two smelters are shown to overlap. ters, as indicated in Figure 10, are significantly dif- Horizontal distribution of aerially deposited heavy ferent in the two forks of Crooked Creek (16). The metals in the affected watersheds is confused and most obvious differences are largely attributable to compounded by episodes of heavy metals released the mentioned pH problem in the west fork. in wastewater effluents and yard runoff. Therefore, An automatic water sampling station located at heavy metal content of stream sediments (Table 5) the confluence of the east and west forks of (13, 14), leaf litter, mosses, and bracket fungi (Table Crooked Creek was arranged to take a series of 6) (15) must be considered the result of accumula- samples during 21 separate storm events. Results tion from all the various sources. Furthermore, obtained from two relatively large storms are sum- horizontal transport of materials down the stream marized in Figure 11. The first depicted storm event

February 1979 29 50000 40000o 50000 Leoad in Loaf Litter 3000?. A Heovy Metals in Loaf Litter (Oh) 0 200001 *5 Zinc O- Of 0 'Coppw A= 01.01 1000I 0 A = Cadmium 0000 o0 7000 'A 5001- 5000 300 *

200[ 0 30001 A 0 0 0 0 0 20001 100 IA0 I 0 0 004 E 0 0 0*. A 70 *0.0 0 0 * 0 0EI00° 50 0 A 0 0 E o 700 30 0 E 500 -i 20 A 00 E 0 90g 0 0 0 - 00000 0000 000 0 0g ; 300 10 A 0 c000 @ 0 7 200 *o *0 0 A o * 0 5 A * *A - AA A AA A~~~ 0~~~~00 *.0 3 A A A 100 A A a *0 ~~~~~~~~~00* 21 A MAA A~A t 70 A ° AAAA AAA 30 A 40 08 A 21 16 6 16 4 12 10 8 6 4 A Is 2422 20 1' I 2 06 L * I I I * I. I 5 10 '5 20 25 0 5 10 IS 20 25 Dstonce from Smelter (tlies) Distonce irom Smelter (miles) A B

FIGURE 9. Heavy metals in leaf litter on transect between AMAX smelter (A) and ASARCO smelters (B): Oh = partially decomposed leaf litter; Of = top layer, recently fallen leaves. After Bolter (12).

Table 5. Stream sediment profiles in Crooked Creek watershed. Station Distance from confluence Pb, gg/g Zn, ,tg/g Cu, ,ug/g Cd, ,ug/g Forks of Crooked Creek" East fork 6300 ft. (impoundment D overflow) 69,056 12,238 839 150 5900 ft 12,250 5,350 2,050 46 5350ft 227,700 46,948 1,455 1,133 4000 ft 14,500 3,800 390 57 1600 ft 13,333 2,867 500 39 100 ft 3,750 1,500 225 32 West fork 6300 ft (impoundment C overflow) 7,874 283 220 45 5900ft 28,000 1,100 500 110 4950 ft 21,667 567 267 57 4850 ft 1,250 240 80 133 4750 ft 8,350 480 185 55 1400 ft 819 97 51 25 Downstream from confluenceb Downstream Crooked Creek 6 miles 283 180 19 2.7 Huzzah Creek 8 miles 35 61 8 8.7 Huzzah Creek 13 miles 64 58 15 3.7 Huzzah Creek 18 miles 31 57 7 0.3 200-325 mesh fractions; data ofJennett (13). Reported values are maximum observed concentrations; data of Proctor (14).

30 Environmental Health Perspectives Table 6. Average heavy metals concentrations in selected specimens in Crooked Creek, 1973-1976. Metal concn, ppm West Forkf' East Fork" I 2 3 4 5 6 Decomposing leaves Pb 39,636 17,821 5,622 44,430 18,768 13,370 Zn 4,192 1,045 1,571 7,608 4,093 4,655 Cu 742 251 228 1,093 723 408 Cd 684 359 629 164 152 185 Composite old and new leaves Pb 31,616 13,869 4,339 35,052 20,058 10,814 Zn 3,183 1,016 1,050 5,366 3,190 3,793 Cu 701 335 185 793 514 390 Cd 765 332 368 199 103 177 Moss Pb 20,892 9,262 3,686 30,627 21,457 9,980 Zn 1,136 359 267 5,397 2,178 1,971 Cu 384 174 135 951 485 304 Cd 70 41 37 74 73 57 Bracket fungi (Fomes and Stereum) Pb 10,661 2,458 880 5,844 2,664 4,115 Zn 925 519 97 533 672 275 Cu 117 150 38 178 160 98 Cd 70 22 28 31 43 20 a See Figure 3 for location of sampling sites.

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FIGURE 10. Water quality profiles of east and west forks of Crooked Creek near AMAX smelter. After Jennett and Foil (16).

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o ___ .AA noI1>4I1n nm 0400) 0600 0800 1000 1200 1400 0600 0800 1000 1200 1400 1600 1800 0200 Time, hrs Time, hrs Storm 7, Jon 10, 1975 Storm 2, Sept. II, 1974 Legend for metals e-* unfIltered sample -- filtered sample

FIGURE 11. Water quality of Crooked Creek during storm runoff. Storm dates: Sept. 11, 1974 and Jan. 10, 1975; automatic water sampler located at confluence of east and west forks. After Jennett and Foil (16). 32 Environmental Health Perspectives (September 11, 1974) resulted in a total rainfall of waters of the west fork measured at the point of 2.25 in., producing a peak flow of 155 cfs approxi- confluence with the east fork of Crooked Creek mately 1 hr after the peak rainrall intensity had oc- remained low, between 4.5 to 5.5 throughout the curred. There had been a smaller (0.21 in.) summer, fall, and most of the winter. It is possible rainstorm two days earlier which produced runoff, that large reservoirs of acidic materials had ac- and rain was detected on eight of the 14 days prior cumulated along the creek bed in subterranean to that sampled storm. aquifers. Such reservoirs may have been estab- A comparison of these two recorded storm events lished over a period of several years, having reveals some interesting points relative to the trans- exhausted local supplies of neutralizing carbonates port of heavy metals from the Crooked Creek wa- present in natural rocks of the area. Alternatively, tershed. Following a period of relatively little pre- the persistent pH problem may indicate leakage of cipitation, the storm runoff from the watershed dis- acidic materials through fissures into the stream's played a drop in pH. The bulk of Cd flow occurred underground aquifers at a point above or within the during the period of low pH and was apparently in a impoundment system upstream from zones of lime dissolved state. Significant quantities of Pb and Zn addition. Low alkalinity of the waters of the west were also present in these initial stages of storm fork creates a situation where radical runoff in the dissolved state. As the storm con- changes in pH may occur upon addition of small tinued, all metal concentrations remained elevated amounts of acid. Further studies are required to in runoff waters, but they were predominantly in a determine the cause of persistent pH problems in particulate state which was not detectable in filtered the west fork of Crooked Creek. Fortunately, as the water samples. Absolute concentrations of Pb and waters of the west fork merge with those of the east Zn were far greater than Cd concentrations. The fork, the pH rapidly rises to normal values for typi- storm event recorded shortly after previous intense cal Ozark streams. runoff activity shows no acidic portion in the hy- Available data suggest that there is a region of drograph. Yet, the suspended particulate matter contamination in the vicinity of the AMAX smelter. shows significant transport of heavy metals, espe- Observed concentrations of heavy metals in water, cially lead, under these conditions of sustained leaf litter, sediments and stream biota drop off runoff. rapidly with distance from the smelter. Because of In other recorded storm events not shown in the its greater solubility under existing physical condi- present figure, Cd was found to be present pre- tions, cadmium is apparently more mobile under dominantly in the dissolved state, while Pb and Zn normal stream flow conditions than lead or zinc. were consistently transported during periods of in- However, during periods of intense rainfall and tense runoff in a particulate, filterable state. These runoff, considerable quantities of all mentioned findings are consistent with data from Butz (17) heavy metals may be flushed into the storm flow as showing greater solubility of Cd salts and lower suspended particulates. Affinity of decomposing tendency of Cd to form organic complexes. Water leaf litter for cationic materials permits the associa- quality data collected by Proctor et al. (14) for sam- tion of all mentioned heavy metals with organic pling stations for the downstream (Table 7) indi- ligands, providing temporary residence of metals cates only nominal concentrations of heavy metals and a vehicle for suspension and transport as de- during normal stream flow. composition proceeds. During the summer of 1977 a program was initi- ated to improve neutralization of effluent waters from impoundment A at the AMAX smelter. De- ASARCO Smelter spite daily addition of lime to the impoundments The ASARCO smelter is located at Glover, Mis- resulting in pH values above 10 observed in souri and has a design capacity of 120,000 tons of effluents at the point of discharge, the pH of the lead per year. The general layout of the plant is

Table 7. Heavy metals concentrations in stream waters of Crooked and Huzzah Creeks, 1975.a Metal concn, ppm Sampling site Distance from smelter, mi Pb Zn Cu Cd Crooked Creek 6 <0.001 0.012 0.001 0.007 Huzzah Creek 8 0.001 0.007 0.010 0.003 Huzzah Creek 13 0.003 0.001 0.010 0.003 Huzzah Creek 18 0.001 0.028 0.004 <0.001 a Data of Proctor (14). Reported values are maximum observed concentrations.

February 1979 33 The accumulation of cadmium in the baghouse materials at ASARCO has already been indicated previously (Table 1). On at least one occasion, when smelting of particularly elevated cad- mium concentrations, cadmium content of baghouse materials approached 7%. At that time, the entire lot of baghouse dust was collected and shipped to El Paso, Texas for recovery of the cad- mium. Baghouse dusts and worn out bags were routinely cycled to the blast furnace. In early oper- ation of the plant, some of the old baghouse bags were hauled to a trash disposal site located to the west of the yard area, a situation perhaps responsi- ble for some vagrant cadmium problems (personal communication, C. F. Bates, ASARCO). The ASARCO smelter is situated alongside Big Creek. A tributary branch cuts directly through the south side of the work yard, under several sets of railroad tracks serving the facility, and alongside the slag storage area. It receives effluent from the plant treatment system at the highway and joins Big Creek approximately 100 yd further downstream. This tributary branch is subject to contamination by heavy metals from a number of recognized sources: spillage from rail cars, erosion from the track area, old trash disposal area, and the slag storage yard. Excessive loss of ore concen- trates from rail cars is evident along the entire route from the truck dumping ramp to the smelter, repre- FIGURE 12. General layout of ASARCO smelter and adjacent Big senting a source of fugitive metals entering this Creek. Numbered circles indicate sampling sites. tributary and also the storm drainage ditch leading from the truck unloading ramp to Big Creek. indicated in Figure 12. Ore concentrates from the In 1975, Hemphill et al. (19) studied the extent of new lead belt, and other mining areas are delivered environmental contamination by heavy metals from to the smelter by rail or truck. The truck dumping ASARCO and offered the following observations. ramp is located at the south end of the work yard, Concentrations of lead in leaves from standing where all concentrates are transferred to rail cars white oak trees (Fig. 13) ranged from 340 ,ug/g dry for eventual delivery to the sinter preparation area. weight near the smelter to a low of 5.6 gg/g at 7 In this smelter, sinter feed is initially moistened and miles in a southeasterly direction. Levels of cad- pelletized prior to roasting. This procedure seems to mium (Fig. 13) ranged from a high of 3.2 ,ug/g, with reduce the quantity of particles blown by only a few samples greater than 1.0,ug/g. /updraft air currents toward the baghouse. Separate baghouses are maintained for sintering and blast furnace operations. Mineralogical analyses by Ar- seneau (18) confirmed the presence of greater pro- portions of PbO and PbSO, in baghouse dusts from ASARCO, while AMAX baghouse dusts, without the benefit of the pelletizing procedures, contain much greater proportions of PbS. Cooled and cleaned sinter and blast furnace gases are passed to the atmosphere through a 602-ft stack. A weather station and a number of SO2 monitors serve to warn plant operators of unfavorable weather conditions or excessive ambient SO2, and operations are scheduled to maintain acceptable levels of atmo- FIGURE 13. Lead and cadmium in white oak leaves near spheric . ASARCO smelter. After Hemphill et al. (/9).

34 Environmental Health Perspectives number of sampling sites near ASARCO smelter are summarized in Figure 15. Industrial effluents and storm runoff waters from the workyard area were shown to have periodic pulses of heavy metals in excess of the guidelines set by the Missouri Department of Natural Re- sources. It is evident from the report that fugitive sediments and dusts in the work yard area fre- quently contributed significant quantities of heavy metals via the drainage ditches and tributary streams into Big Creek. FIGURE 14. Lead and cadmium in decomposing forest litter near Big Creek has had a history of undesirable alter- the ASARCO smelter. After Hemphill et al. (19). ations due to industrial effluents with decreasing benthic diversity and undesirable algal blooms at various times extending as far downstream as An- Distribution patterns for lead and cadmium in the napolis, approximately 8 miles from the smelter. A decomposing forest litter in the vicinity of the report prepared by Midwest Research Institute [see ASARCO smelter are shown in Figure 14. The in- Hemphill (19)] in 1974 for the Environmental Pro- fluence of the AMAX smelter is seen clearly in the tection Agency indicated that in the absence of any northwestern portion of the area. air control equipment, the ASARCO A comparison of metal content of standing and smelter would emit over 5600 lb/hr particulate mat- matted pasture grasses showed markedly higher ter, approximately 11% of this emission being lead. concentrations in the latter. Lead and cadmium With current equipment, however, concentrations in matted pasture grass from a total particulate emissions have been reduced to

I I AS 1.4 A50 8; A<0.5 A37 A C\' 7 . A54 A 1.5 6- 96- A119 A 1.4 5- A167 Cd A 1.5 4- A5 Pb A89 Al A4 -4 4- A236 3- A 114 A284 A 7 3- 2- A22 A 406 A 1640 A2 2- I A26 A89 A 1900 0- t *Smelter A14700 ±1.4 A44 0- j52 *Smelter - A 1.4 88 ASO50 A 0.5 A13 I1- A239 A Al A9 A81 A 2890 2-<0.5 A? A63 A1690 A, A.<0.5 AO.5 2- 82 463 A 792 3 <0.5 A5 AA36 A37 3- A704 A0.5 4- A2.5 A 4- A59 A178 5- AlI A25 A I 5- *-77 6- A106 A 6- 7- A 106 7- 8- Al A92 9 v__.. L. -.. 41 i -1 I L .1 J . 7' 6 5 4 3 2 I 0 1 2 3 4 8 7 6 5 4 3 2 1 0 I 2 3 4 5 MILES MILES

FIGURE 15. Lead and cadmium in matted pasture grasses near the ASARCO smelter. After Hemphill et al. (19).

February 1979 35 Table 8. Representative heavy metals content of water, stream sediments, and leaf litter from sampling sites near ASARCO smelter, 1976-77. Metals concn, ppm Station Material Pb Zn Cu Cd 6 Sediment, 80 mesh 147,000 29,000 7,170 450 Sediment, 80 mesh 26,700 28,500 421 2,990 Leaf litter 6,211 6,790 171 769 1, 8 Water <0.2 0.4 <0.02 0.12 Sediment, 80 mesh 29,300 23,670 1,206 9,400 Leaf litter 18,400 16,800 531 1,780 2 Water 0.3 0.45 <.02 0.12 Sediment, 80 mesh 32,300 22,660 1,086 3,330 Leaf litter 12,510 10,800 416 911 3 Water <0.2 0.13 <0.02 0.04 Sediment, 80 mesh 19,600 20,900 588 592 Leaf litter 8,520 1,400 127 312 4 Water <0.2 0.08 <0.02 <0.02 Sediment, 80 mesh 2,480 890 223 37 Leaf litter 6,767 3,050 156 236 5 Water <0.2 <0.03 <0.02 <0.02 Sediment 13,080 12,600 238 696 Leaf litter 4,450 1,490 114 325 13 Sediments 28,800 10,600 573 136 Leaf litter 34,600 4,580 338 145 14 Sediments 11,600 3,400 266 29 Leaflitter 17,240 3,480 424 78 approximately 39 lb/hr approximately 6.6 lb being dusts and slurries associated with sintering and lead. blast furnace gases. The handling and processing of Samples of water, stream sediments and leaf litter these baghouse materials and slurries as well as dis- along the stream beds collected during 1976-1977 posal of old worn-out bags requires special consid- were recently analyzed for purposes of comparison eration as sources of potentially hazardous levels of with earlier data and evaluation of current control cadmium. Where possible, the industry should be measures. These current data are shown in Table 8 encouraged to recover the cadmium present in such and reflect residual heavy metals or those continu- materials, since there is no other satisfactory sink ally entering the stream system from established for its removal other than fugitive emissions. fugitive sources. During the summer of 1977, Big The lead industries have supported a number of Creek displayed a dense diatomaceous mat which studies to determine sources of fugitive heavy met- covered more than 80%o of the stream bottom for als and has responded to correct environmental more than a mile downstream from the smelter. problems as these have become known. However, Dominant algal forms included the diatom, Cym- despite consistent efforts by the industry to curtail bella, and unidentified blue-green filamentous fugitive metals and to avoid and minimize environ- algae. Populations of normal consumer organisms mental effects of their operations, there remains the were sharply reduced compared with regions of the constant potential of environmental contamination stream upstream from the smelter. Similar algal in close proximity to lead smelters. Current levels blooms have been reported in new lead belt streams of cadmium contamination are obviously high in the receiving effluents from mine-mill complexes with vicinity of the smelters. These facts emphasize the histories of elevated dissolved zinc and residual obvious necessity of establishing a safe "green milling reagents (20). belt" or buffer around such operations. The smelters should be located, when possible, in sparsely popu- Conclusions lated areas. Under present control conditions, environmental Primary lead smelters in Missouri's new lead belt contamination by heavy metals, including cad- were recognized as potential sources of environ- mium, drops off rapidly with increasing distance mental cadmium as well as lead, zinc, and copper. from the smelters. Cadmium, lead, zinc, and copper Cadmium tends to concentrate in the baghouse present in the deciduous forest of the new lead belt

36 Environmental Health Perspectives appear to have an affinity for the organic debris or production use and disposal of cadmium. In: Cadmium 77, Proceedings First International Cadmium Conference, decomposing forest litter and tend to accumulate Drogher Press, Dorsett, England, 1977, pp. 45-49. there. Transport of these heavy metals may occur 4. Von Ropenack, A. Emission control in cadmium metal pro- during storm events, as metal-laden organic par- duction. In: Cadmium 77, Proceedings First International ticulates are swept into regional streams. The pres- Cadmium Conference, Drogher Press, Dorsett, England, ence of or organic acids, originating from 1977, pp. 49-53. 5. Dugdale, P. J., and Hummel, B. L. Cadmium in the lead natural processes of decomposition or from indus- smelter at Belledune: its association with heavy metals in the trial sources may accelerate the dissolution of metal ecosystem. In: Cadmium 77, Proceedings First International salts or complexes and contribute to transport of the Cadmium Conference, Drogher Press, Dorsett, England, metals in the dissolved state. Because of the 1977, pp. 53-75. 6. Wixson, B. G., et al. The Missouri Lead Study. National characteristics of cadmium with regard to solubility Science Foundation, Washington, D. C., 1977. and complexing ability, it tends to be more mobile 7. Bolter, E. Soils and geochemical studies. In: The Missouri than lead, zinc, or copper. Lead Study, B. G. Wixson, Ed., National Science Founda- Much remains to be known about the possible tion, Washington, D. C., 1977, p. 95. toxic effects cadmium and associated heavy metals 8. McAllister, W. Study of a lead smelter wastewater treatment process. M. S. Thesis, University ofMissouri, Rolla, Missouri, may have on the normal biota of a deciduous forest 1978. ecosystem. The continued survival of diverse and 9. Lowsley, I. H., Jr. Air quality. In: The Missouri Lead Study, typical biological communities in areas known to be B. G. Wixson, Ed., National Science Foundation, contaminated by heavy metals indicates a need for Washington, D. C., 1977, p. 52. the scientific community to gain further insight into 10. Lowsley, I. H., Jr. Air quality. In: Continuation of En- vironmental Studies Around the AMAX-Homestake Lead the problems of bioavailability, cellular transport Smelter Near Boss, Missouri. 1978. Final report submitted mechanisms, and resistance characteristics in natu- to AMAX-Homestake Lead Tollers. University of ral biological communities. Missouri-Rolla, 1978. More precise definitions of toxic effects and 11. Hemphill, D. D. Accumulation of toxic heavy metals by veg- etation. In: The Missouri Lead Study, B. G. Wixson, Ed., hazardous levels for normal terrestrial and aquatic National Science Foundation, Washington, D. C., 1977, organisms are badly needed. Industry should be en- p. 544. couraged to continue their self-evaluation and 12. Bolter, E. Soils and geochemical study. In: An Interdiscipli- monitoring efforts and to employ the best possible nary Investigation of Environmental Pollution by Lead and means of limiting or eliminating release of poten- Other Heavy Metals from Industrial Development in the New Lead Belt of Southeastern Missouri. B. G. Wixson, tially hazardous materials into the environment. Ed., National Science Foundation, New York, 1974, p. 97. Many of the problems associated with heavy metal 13. Jennett, J. C., and Wixson, B. G. Water quality studies. In: contamination may be avoided or certainly im- The Missouri Lead Study, B. G. Wixson, Ed., National Sci- proved by proper and consistent housekeeping pro- ence Foundation, Washington, D. C., 1977, p. 179. 14. Proctor, P. D., Butz, T., and Sinha, B. Heavy metals addi- cedures. In a large industrial operation, however, tions to surface waters, stream sediment and selected such housekeeping details are perhaps easily ob- aquatic life, Meramec Park Reservoir Drainage Basin, Mis- served, but difficult to correct. Nevertheless, the souri. Completion report, USDI Office of Water Resources, cooperative and professional attitude of industry Project No. A-072-MO, 1975. representatives is appreciated. 15. Wixson, B. G., Gale, N. L., and Downey, K. Control of environmental contamination by cadmium, lead and zinc The authors gratefully acknowledge the support of the Smelter near a new lead belt smelter. In: Trace Substances in En- Environmental Research Association, AMAX-Homestake Lead vironmental Health, Vol. XI. D. D. Hemphill, Ed. Univer- Toilers, Inc., ASARCO, and the National Science Foundation. sity of Missouri, Columbia, Mo., 1975, p. 455. We also acknowledge the cooperative attitude among the various 16. Jennett, J. C., and Foil, J. Trace metal transport from min- concerned lead industries, the university, state, and federal reg- ing, milling and smelting watersheds. J. Water Pollut. Con- ulatory agencies who are hopeful that such applied environmen- trol Fed., in press. tal studies may lead to an improved understanding of the be- 17. Butz, T. Chemical and mineralogical characteristics of par- havior of heavy metals in the environment. ticulates in stack emissions from two lead smelters in South- east Missouri. Ph.D. Dissertation, University of Missouri- Rolla, 1976. REFERENCES 18. Arseneau, J. Chemical and mineralogical characteristics of particulates in stack emissions from two lead smelters in 1. Cadmium Association, Cadmium Council, and International Southeast Missouri. Master's Thesis. University of Lead Zinc Research Organization. In: Cadmium 77, Pro- Missouri-Rolla, 1976. ceedings First International Cadmium Conference, San 19. Hemphill, D. D. Report of cooperative study for the impact Francisco, Metal Bulletin, Drogher Press, Dorsett, England, of a lead smelter operations on the local environment, En- 1977. vironmental Trace Substances Research Center, University 2. Stubbs, R. L. Cadmium-the metal of benign neglect. In: of Missouri-Columbia, 1975. Cadmium 77, Proceedings First International Cadmium 20. Gale, N. L., and Wixson, B. G. Water quality-biological Conference, Drogher Press, Dorsett, England, 1977, aspects. In: The Missouri Lead Study, B. G. Wixson, Ed., pp. 7-12. National Science Foundation, Washington, D. C., 1977, 3. Barbour, A. K. Environmental Control techniques for the p. 400. February 1979 37